The present disclosure is directed to a method for improving poultry tissues or the meat and eggs produced therefrom through the utilization of plant-derived stearidonic acid (“SDA”) or SDA oil in animal feed. Specifically, the inventors provide techniques and methods for the utilization of transgenic plant-derived SDA compositions in feed products that improve the nutritional quality of poultry derived products or in the productivity of the animals themselves.
Many studies have made a physiological link between dietary fats and pathologies such as obesity and atherosclerosis. In some instances, consumption of fats has been discouraged by the medical establishment. More recently, the qualitative differences between dietary fats and their health benefits have been recognized.
Recent studies have determined that despite their relatively simple biological structures there are some types of fats that appear to improve body function in some ways and that may, in fact, be essential to certain physiological processes. The wider class of fat molecules includes fatty acids, isoprenols, steroids, other lipids and oil-soluble vitamins. Among these are the fatty acids. The fatty acids are carboxylic acids, which have from 2 to 26 carbon atoms in their “backbone,” with none or few desaturated sites in their carbohydrate structure. They generally have dissociation constants (pKa) of about 4.5 indicating that in normal body conditions (physiological pH of 7.4) the vast majority will be in a dissociated form.
With continued experimentation workers in the field have begun to understand the nutritional need for fats and in particular fatty acids in the diet. For this reason, many in the food industry have begun to focus on fatty acids and lipid technology as a new focus for food production, with its consequent benefits for the animals consuming the modified feed and in products derived from those animals for human consumption. This focus has been particularly intense for the production and incorporation of omega-3 fatty acids into the diet. Omega-3 fatty acids are long-chain polyunsaturated fatty acids (18-22 carbon atoms in chain length) with the first of the double bonds (“unsaturations”) beginning with the third carbon atom from the methyl end of the molecule. They are called “polyunsaturated” because their molecules have two or more double bonds “unsaturations” in their carbohydrate chain. They are termed “long-chain” fatty acids since their carbon backbone has at least 18 carbon atoms. In addition to stearidonic acid “SDA” the omega-3 family of fatty acids includes alpha-linolenic acid (“ALA”), eicosatetraenoic acid (ETA), eicosapentaenoic acid (“EPA”), docosapentaenoic acid (DPA), and docosahexaenoic acid (“DHA”). ALA can be considered a “base” omega-3 fatty acid, from which EPA and DHA are made in the body through a series of enzymatic reactions, including the production of SDA. Most nutritionists point to DHA and EPA as the most physiologically important of the omega-3 fatty acids with the most beneficial effects. However, SDA has also been shown to have significant health benefits. See for example, U.S. Pat. No. 7,163,960 herein incorporated by reference.
The synthesis processes from ALA is called “elongation” (i.e., the molecule becomes longer by incorporating new carbon atoms) and “desaturation” (i.e., new double bonds are created), respectively. In nature, ALA is primarily found in certain plant leaves and seeds (e.g., flax) while EPA and DHA mostly occur in the tissues of cold-water predatory fish (e.g., tuna, trout, sardines and salmon), and in some marine algae or microbes that they feed upon.
Along with the movement of food companies to develop and deliver essential fats and oils as an important component in a healthy human diet, governments have begun developing regulations pushing for the adoption of PUFA's in the diet. The difficulty in supplying these needs has been the inability to develop a large enough supply of omega-3 oil to meet growing marketplace demand. As already mentioned, the omega-3 fatty acids commercially deemed to be of highest value, EPA and DHA, which are provided in marine sources, also chemically oxidize very quickly over time limiting commercial availability. Importantly, during the rapid process of EPA and DHA degradation these long chain fatty acids develop rancid and profoundly unsatisfactory sensory properties (e.g., fishy odor and taste) that make their inclusion in many foodstuffs difficult or impossible from a commercial acceptance perspective. Furthermore, as typical poultry products are cooked at least once and more often, at least twice (i.e., initially by the manufacture and then reheated by the consumer), oxidation of the EPA and DHA is even further increased, resulting in an even more unsatisfactory sensory product.
In addition, with increased demand for omega-3 fatty acids has come the realization that already depleted global fish stocks cannot meet any significant growth in future human nutritional needs for omega-3's. These limitations on supply, stability and sourcing greatly increase cost and correspondingly limit the availability of dietary omega-3's.
Suboptimal nutrition and growth are limiting factors in animal productivity. Basic information regarding these processes in agriculturally important animals, including common commercial poultry, is lacking. New knowledge in these areas is needed to improve animal production and control muscling, growth, reproductive capacity and metabolism. Research is also needed to identify biological mechanisms for increasing dietary nutrient availability, directing nutrient partitioning toward more protein and less fat, enhancing nutrient composition in animal products, and minimizing excretion of nutrients as waste products. It is also desirable to develop a system that is capable of determining if a particular feed is useful in enhancing animal productivity. Examples of suitable evaluation criteria include a feed cost per unit animal weight gain basis, an animal production rate basis (e.g., based upon a rate of animal weight gain or a rate of production of an animal product, such as milk or eggs), and a feed amount per unit of animal weight gain basis.
Metabolic modifiers, such as certain fatty acids, are a group of compounds that modify animal metabolism in specific and directed ways if provided in the diet. Metabolic modifiers generally have the overall effect of improving productive efficiency (e.g., weight gain or milk yield per feed unit), improving carcass composition (e.g., meat-to-fat ratio) in growing animals, increasing milk yield in lactating animals and decreasing animal waste. Prior research has indicated that supplementation with certain dietary fatty acids, acting as metabolic modifiers, can enhance animal productivity (Calder (2002); Klasing (2000); and, Mattos (2000)).
Accordingly a need exists to enhance the nutritional quality and productivity of farm animals and products produced therefrom. The SDA compositions of the current disclosure not only provide needed dietary fat for specific animal species, including poultry, but also provide other dietary improvements for the commercial production of animals as well as gains in animal productivity. The feed compositions of the current disclosure comprise SDA compositions that can be used in producing an enhanced feed for poultry containing the SDA compositions of the disclosure.
In addition, a need exists to provide a consumer acceptable means of delivering EPA and DHA or critical precursors in food formulations in a commercially acceptable way. The current disclosure provides an alternative to fish or microbe-supplied omega-3 fatty acids in the form of poultry meat and eggs comprising beneficial omega-3 fatty acids and does so utilizing a comparatively chemically stable omega-3 fatty acid, SDA, as a source that offers improved cost-effective production and abundant supply as derived from transgenic plants.
According to embodiments of the current disclosure, the preferred plant species that could be modified to reasonably supply demand are: soybeans, corn, and canola, but other many plants could also be included as needed and as scientifically practicable. Once produced, the SDA of the disclosure can be used to improve the health characteristics of a great variety of food products. This production can also be scaled-up as needed to both reduce the need to harvest wild fish stocks and to provide essential fatty acid (FA) components for aquaculture operations, each greatly easing pressure on global fisheries.
Previous attempts to increase the concentration of beneficial fatty acids in poultry have included supplementing the diet of the poultry with ALA, EPA, or DHA. Omega-3 fatty acids have been investigated as a potential way to improve performance and meat quality in pigs and poultry. In the literature, some trials indicated positive responses and others indicated that there may be negative responses in growth response to omega-3 FA. The disparity of growth performance response was largely due to differences in source of the omega-3 FA and in the other dietary FA present. In reviewing the previous research, it was apparent that under extreme immune pressure the likelihood of a positive growth response to omega-3 FA was increased. The immune data suggest that a balanced omega-3 and omega-6 FA diet provides for the optimal immune function, but the most appropriate balance has not been identified.
Some attempts at incorporation of omega-3 fatty acids into poultry products have been described in the art. However, existing methods include addition of highly unstable EPA or DHA which are less stable and more difficult to obtain; or incorporation of traditional omega-3 fatty acids such as alpha-linolenic acid (ALA), which are not converted to the beneficial forms efficiently enough to be practical. Nutritional studies have shown that, compared to ALA, SDA is 3 to 4 times more efficiently converted in vivo to EPA in humans. (Ursin, 2003).
Surprisingly, the inventors have found that feeding poultry SDA compositions from transgenic plant sources is highly effective in increasing the omega-3 fatty acid levels of SDA (18:4), ETA (omega-3 20:4), EPA (eicosapentaenoic acid), DPA (docosapentaenoic acid), DHA (docosahexaenoic acid) and decreases in the levels of the omega-6 fatty acids ARA (arachidonic acid), and docosatetraenoic acid (DTA, omega-6 22:4) and thereby improves the omega-6 to omega-3 fatty acid ratio. Furthermore, plant sources, such as soybean oil, have been found to provide more stable fatty acids to the product. Specifically, SDA soybean oil was shown to take 5 to 10 times longer to oxidize as measured by peroxide values and anisidine values as compared to fish oils in stability tests.
Previous research has shown little to no incorporation of SDA in humans. See for example James et al. (2003), Harris et al. (2007), and Miles et al. (2004).
Furthermore, there was greater incorporation of SDA into poultry meat when using the SDA soybean oil as compared to using the SDA ethyl ester. More particularly, it has been found that pancreatic lipase resistance (i.e., resistance to pancreatic lipase hydrolysis) results in lower absorption of fatty acids in humans. It has further been reported that all fatty acid ethyl esters seem to resist pancreatic lipase hydrolysis (Lawson, 1988). Accordingly, it is believed that this lipase resistance results in lower absorption of SDA into the poultry when using SDA ethyl ester as compared to SDA soybean oil.
Furthermore, the inventors have found unexpected decreases in, 18:1 (oleic acid) and (C18:2) in both breast and thigh meat with and without skin. Overall, the inventors believe this constitutes for a healthier composition of the fatty acid profile in chicken feed with SDA.
Furthermore, the inventors have found no significant difference in the palatability, flavor, tenderness, or overall consumer acceptability, as previously described using methods such as in U.S. Pat. No. 6,716,460. Additionally, the methods of the present disclosure do not require the administration of SDA from a concentrated source.
An improved ratio of omega-3 fatty acids in broilers is also accessible by feeding fish oil comprising DHA. However, the literature describes that such chicken meat is associated with undesirable side affects such as stability and taste and smell properties. Adverse taste, smell, and stability were not found in the methods and products of the present disclosure. SDA feed comprising whole foods, unlike the omega 3 fatty acids commonly described in the literature, is uniquely suited for feed compositions which yield healthy and stable poultry products.
A further advantage of feeding SDA over alpha linolenic acid (ALA) is that SDA circumvents the limiting reaction of the delta-6 desaturase and is therefore much more efficiently converted to the long chain PUFA's EPA, DPA, and DHA.